Defect reduction in electrodeposited copper for semiconductor applications

ABSTRACT

A method for electroplating a copper deposit onto a semiconductor integrated circuit device substrate having submicron-sized features, and a concentrate for forming a corresponding electroplating bath. A substrate is immersed into an electroplating bath formed from the concentrate including ionic copper and an effective amount of a defect reducing agent, and electroplating the copper deposit from the bath onto the substrate to fill the submicron-sized reliefs. The occurrence of protrusion defects from superfilling, surface roughness, and voiding due to uneven growth are reduced, and macro-scale planarity across the wafer is improved.

REFERENCE TO RELATED APPLICATION

This is a divisional of application Ser. No. 10/091,106 filed Mar. 5,2002, now U.S. Pat. No. 7,316,772.

BACKGROUND OF THE INVENTION

This invention relates to a method, compositions, and additives forelectrolytic copper metallization of silicon wafers in the manufactureof semiconductor integrated circuit (IC) devices.

The demand for manufacturing semiconductor IC devices such as computerchips with high circuit speed, high packing density and low powerdissipation requires the downward scaling of feature sizes inultra-large-scale integration (ULSI) and very-large-scale integration(VLSI) structures. The trend to smaller chip sizes and increased circuitdensity requires the miniaturization of interconnect features whichseverely penalizes the overall performance of the structure because ofincreasing interconnect resistance and reliability concerns such aselectromigration.

Traditionally, such structures had used aluminum and aluminum alloys asthe metallization on silicon wafers with silicon dioxide being thedielectric material. In general, openings are formed in the dielectriclayer in the shape of vias and trenches after metallization to form theinterconnects. Increased miniaturization is reducing the openings tosubmicron sizes (e.g., 0.5 micron and lower).

To achieve further miniaturization of the device, copper has beenintroduced instead of aluminum as the metal to form the connection linesand interconnects in the chip. Copper metallization is carried out afterforming the interconnects. Copper has a lower resistivity than aluminumand the thickness of a copper line for the same resistance can bethinner than that of an aluminum line. Copper-based interconnectstherefore represent the future trend in the fabrication of such devices.

Copper can be deposited on substrates by plating (such as electrolessand electrolytic), sputtering, plasma vapor deposition (PVD), andchemical vapor deposition (CVD). It is generally recognizedelectrochemical deposition is the best method to apply copper to thedevice since it can provide high deposition rates and low tool costs.However, plating methods must meet the stringent requirements of thesemiconductor industry. For example, the copper deposits must be uniformand capable of flawlessly filling the extremely small trenches and viasof the device. The plating process must also be capable of beingcontrolled so that process variation is minimized. The deposition ofcopper from acid copper baths is recognized in the electronics industryas the leading candidate to copper plate integrated circuit devices.

Copper electroplating, in general, involves deposition of a copper layeronto a surface by means of electrolysis using a consumable copperelectrode or an insoluble anode.

Regardless of the method used to deposit copper on the substrate surfaceimpurities may be co-deposited with the copper and other morphologicaldefects introduced. In IC fabrication it is important that impurityparticles not be present in the electrolyte but such impurities mayresult from anode sludges formed during the plating operation.

Other micro-defects which adversely affect conductivity in depositedcopper result from internal voiding and voiding attributable todetachment of the deposited copper from the walls of features includingvias and trenches.

SUMMARY OF THE INVENTION

It is an object of the invention, therefore, to provide a method andcompositions for electroplating copper to fill submicron-sized featuresof integrated circuit devices with fewer defects and improved surfacemorphology.

Briefly, therefore, the invention is direct to a method forelectroplating a copper deposit onto a semiconductor integrated circuitdevice substrate having submicron-sized features. The method involvesimmersing the substrate into an electroplating bath including ioniccopper and an effective amount of a defect reducing agent; andelectroplating the copper deposit from the bath onto the substrate tofill the submicron-sized reliefs. The occurrence of protrusion defectsfrom superfilling, surface roughness, and voiding due to uneven growthare reduced, and macro-scale planarity across the wafer is improved.

In another aspect, the invention is directed to a concentrate forpreparation of a copper electroplating bath for electroplating a copperdeposit onto a semiconductor integrated circuit device substrate havingsubmicron-sized features. The concentrate has a defect reducing agentwhich reduces the occurrence of protrusion defects from superfilling,surface roughness, and voiding due to uneven growth, and improvesmacro-scale planarity across the wafer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-4 are 50,000× photomicrographs of four cross sections of copperdeposits with the amount of defect reducing agent increasing from 0 ml/Lto 1.5 ml/L to 2.0 ml/L to 5.0 ml/L.

FIGS. 5 and 6 are 120,000× photomicrographs of a cross section of acopper deposit taken at successive intervals during deposition.

FIGS. 7 and 8 are 25,000× photomicrographs of a cross section of acopper deposit taken at successive intervals during deposition.

FIGS. 9 and 10 are schematic representations of alternative platingsystems for carrying out the method of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In accordance with this invention, a compound is incorporated into theplating bath which has the effect of reducing formation ofmicro-defects. Certain defects in deposited copper can occur due tolocally uneven growth of copper crystals. Other defects formed afterdeposition, applicants believe, can be attributed to recrystallizationand grain growth in the deposit. In particular, there are changes involume resulting from grain growth, which changes in volume producestress-induced defects. These volume changes also cause a degree ofdetachment of the deposit from the via and trench walls, whichconstitute defects. And recrystallization causes spontaneous internalvoids as grain boundaries are eliminated.

Superfilling is rapid bottom up deposition within the features which iscreated by a two additive system consisting of a suppressor andaccelerator. Generally the bottom-up filling created by a two-partsystem tends to form a bump or protruding surface defect over thefeatures. The present invention involves a third component whichinhibits the formation of this type of defect. The mechanism of thisinhibition is based on leveling achieved by a stronger suppression ofdeposition in the areas of accelerated growth rate.

Not all agents which are capable of this leveling suppression reducemultiple types of defects as described herein. Certain classes ofcompounds have been identified herein to reduce multiple types ofdefects.

It has also been observed that these leveling compounds added to theplating bath have an effect of decreasing voiding by inhibiting, or atleast slowing the rate of, recrystallization in the deposit. The defectreducer component of the invention is either an aliphatic polyamine or apolymeric nitrogen heterocyclic. In either case it is selected from suchcompounds which are soluble in a copper plating bath, retain theirfunctionality under electrolytic conditions, and do not yielddeleterious by-products under electrolytic conditions, at least neitherimmediately nor shortly thereafter.

One example of a suitable defect reducing agent is a reaction product ofbenzyl chloride and hydroxyethyl polyethyleneimine (available under thetradename Lupasol SC 61B from BASF Corporation of Rensselear, N.Y.).

Another suitable defect reducing agent is a reaction product of benzylchloride and polyethyleneimine.

A further suitable defect reducing agent is the reaction product of1-chloromethylnaphthalene and hydroxyethyl polyethyleneimine (availableunder the tradename Lupasol SC 61B from BASF Corporation of Rensselear,N.Y.). Polyvinylpyridines and their quaternized salts, andpolyvinylimidazole and its salts are also suitable.

As noted above, the defect reducer of the invention has an effect ofdecreasing voiding by inhibiting, or at least slowing the rate of,recrystallization in the deposit. After annealing, and even in theabsence of a specific elevated temperature annealing operation,individual grains in deposited copper have a tendency to recrystallizeand grow. FIG. 1 illustrates this grain growth, as large grains can beseen in the cross-section of the deposit plated without the defectreducing agent of the invention. As can be seen in FIGS. 2, 3, and 4,the addition of the defect-reducing agent of the invention in increasingamounts slows the formation of the larger grains. The deposits in thesefigures were made with 1.5 ml/L, 2.0 ml/L, and 5.0 ml/L, respectively,of the defect reducer of the invention in the bath. By slowing the rateof recrystallization and grain growth, it is believed that internalstresses during recrystallization and grain growth are reduced, whichstresses tend to manifest themselves as internal voids. Thus, overallinternal voiding is reduced.

An aspect of the defect reducing agent of the invention is that itincreases the overall chloride content of the copper deposit as comparedto the chloride content of a deposit made under identical conditionswithout the agent. The overall chloride content of the deposit employingthe agent of the invention is, for example, at least about 2.0×10¹⁹atom/cm³. In a different embodiment, the overall chloride content of thedeposit employing the agent of the invention is, for example, at leastabout 4.0×10¹⁹ atom/cm³ as compared to a deposit made under identicalconditions without the agent which has less than about 1.5×10¹⁹atom/cm³. In one embodiment, the overall chloride content of the depositis between about 4.0×10¹⁹ atom/cm³ and about 25×10¹⁹ atom/cm³. Inanother embodiment, the elevated chloride content is greater than about1×10¹⁹ atom/cm³, which is greater than in a comparable deposit under thesame conditions without the agent. Experimental results reveal thatincluding 2.0 ml/L of defect reducing agent in an electroplating bathincreased the chloride content from 0.34×10¹⁹ atom/cm³ without the agentto 5.18×10¹⁹ atom/cm³ with the agent. In other baths with different bathcompositions and different deposition parameters, including 2.0 ml/L ofdefect reducing agent in the bath increased the chloride content from1.07×10¹⁹ atom/cm³ without the agent to 18.0×10¹⁹ atom/cm³ with theagent, and from 0.17×10¹⁹ atom/cm³ without the agent to 11.6×10¹⁹atom/cm³ with the agent. In still other baths with different bathcompositions and different deposition parameters, including 1.0 ml/L ofdefect reducing agent in the bath increased the chloride content fromabout 0.1×10¹⁹ atom/cm³ without the agent to 0.9×10¹⁹ atom/cm³, 1.0×10¹⁹atom/cm³, 1.0×10¹⁹ atom/cm³, 1.2×10¹⁹ atom/cm³, and 3.0×10¹⁹ atom/cm³with the agent in separate experiments.

In another aspect the defect reducing agent of the invention wasobserved to increase the overall nitrogen content of the copper depositas compared to a deposit made under identical conditions without theagent. The overall nitrogen content of the deposit using the defectreducing agent of the invention is, for example, at least about 1.0×10¹⁸atom/cm³. In one embodiment, the overall nitrogen content of the depositis between about 1.0×10¹⁸ atom/cm³ and about 4.0×10¹⁸ atom/cm³.Experimental results reveal that including 2.0 ml/L of defect reducingagent in an electroplating bath increased the nitrogen content from0.13×10¹⁸ atom/cm³ without the agent to 1.11×10¹⁸ atom/cm³ with theagent. In other baths with different bath compositions and differentdeposition parameters, including 2.0 ml/L of defect reducing agent inthe bath increased the nitrogen content from 0.53×10¹⁸ atom/cm³ withoutthe agent to 4.81×10¹⁸ atom/cm³ with the agent, and from 0.21×10¹⁸atom/cm³ without the agent to 2.13×10¹⁸ atom/cm³ with the agent.

The defect reducing agent of the invention also is believed to increasethe overall sulfur content of the copper deposit as compared to adeposit made under identical conditions without the agent. The overallsulfur content of the deposit is, for example, at least about 3.0×10¹⁸atom/cm³. In one embodiment, the overall sulfur content of the depositis between about 3.0×10¹⁸ atom/cm³ and about 15.0×10¹⁸ atom/cm³. Instill another embodiment, the overall sulfur content of the deposit isat least about 1.5×10¹⁸ atom/cm³ as compared to less than about 1.0×10¹⁸atom/cm³ for a deposit made under identical conditions without theagent. Experimental results reveal that including 2.0 ml/L of defectreducing agent in an electroplating bath increased the sulfur contentfrom 0.38×10¹⁸ atom/cm³ without the agent to 3.72×10¹⁸ atom/cm³ with theagent. In other baths with different bath compositions and differentdeposition parameters, including 2.0 ml/L of defect reducing agent inthe bath increased the sulfur content from 1.72×10¹⁸ atom/cm³ withoutthe agent to 13.2×10¹⁸ atom/cm³ with the agent, and from 0.48×10¹⁸atom/cm³ without the agent to 8.12×10¹⁸ atom/cm³ with the agent. Inother baths with different bath compositions and different depositionparameters, including 1.0 ml/L of defect reducing agent in the bathincreased the sulfur content from 0.8×10¹⁸ atom/cm³ without the agent to1.5×10¹⁸ atom/cm³, 2.5×10¹⁸ atom/cm³, 2.5×10¹⁸ atom/cm³, and 2.5×10¹⁸atom/cm³ with the agent.

The compounds of the invention have the advantage of leveling. Inparticular, deposited metal tends to follow, and in fact amplify,changes in elevation corresponding to features on the substrate, asillustrated in FIGS. 5-8. The compounds of the invention have a levelingeffect on the deposit, as illustrated in FIGS. 5-8 where the upperseries in each figure illustrate surface perturbations in the depositover features on a wafer without using the defect reducer and leveler ofthe invention. The lower series of photomicrographs in each figure, incontrast, illustrate much milder perturbations, an effect which isdriven by the greater adsorption of the defect reducer that slows downthe deposition in these locations. In those areas where the surfacetopography is relieved due to the presence of a trench, relatively morecopper is deposited onto such relieved surface areas than ontounrelieved surface areas. This yields an overall copper deposit surfacewhich is more level than a comparable overall deposit surfaceelectroplated without the defect reducing agent. With this more leveldeposit, the size of the overall deposit is reduced, as the features arefilled in a more level manner. Relatively more copper is deposited ontorelieved surface areas than onto unrelieved surface areas, such that theoverall deposit is more level than an overall deposit surfaceelectroplated without the defect reducing agent. There are thereforesavings in terms of the amount of metal to be deposited and, perhapsmore significantly, in terms of deposition time to fill the features.The overall deposit thickness to achieve a minimum thickness at alllocations of the deposit is therefore thinner than an overall depositrequired to achieve the same minimum thickness by electroplating withoutthe defect reducing agent.

In addition, due to the relatively high resistance from the copper seedlayer that carries the current from the edge to the center of the waferfor deposition, the copper deposit is thicker on the edge. By using thedefect reducing agent the distribution of the deposited copper over thesubstrate surface is improved. In one embodiment, the deposit thicknessis about 1 micron, and the thickness varies by no more than 0.1 micronacross the deposit, the deposit thickness being measured from the uppersurface of the deposit to the substrate surface at its thickest point.

A further significant advantage of this leveling effect is that lessmaterial has to be removed in post-deposition operations. For example,chemical mechanical polishing (CMP) is used to reveal the underlyingfeatures. The more level deposit of the invention corresponds to areduction in the amount of metal which must be deposited, thereforeresulting in less removal later by CMP. There is a reduction in theamount of scrapped metal and, more significantly, a reduction in thetime required for the CMP operation. The material removal operation isalso less severe which, coupled with the reduced duration, correspondsto a reduction in the tendency of the material removal operation toimpart defects.

A feature of the invention is that what is known as high current densityedge effect is reduced. In particular, there is a tendency for burningto occur at the edge of a substrate where current density is highest,which burning detracts from brightness and reduces yield. The defectreducer and leveler of the invention reduces this effect.

Referring to FIG. 9, a preferred plating system is shown generally as 10and is used for electroplating copper onto a substrate 12. The platingsystem 10 and method are described with reference to plating a siliconwafer using an insoluble anode but it will be appreciated by thoseskilled in the art that other substrates may be plated.

The preferred plating system 10 comprises an electroplating tank 11which holds copper electrolyte 27 and which is made of a suitablematerial such as plastic or other material inert to the electrolyticplating solution. The tank is preferably cylindrical especially forwafer plating. A cathode 12 is horizontally disposed at the upper partof tank 11 and may be any type substrate such as a silicon wafer havingopenings such as trenches and vias. The wafer substrate 12 a istypically coated with a seed layer of copper or other metal to initiateplating thereon. A copper seed layer may be applied by CVD, PVD, or thelike. An anode 13 is also preferably circular for wafer plating and ishorizontally disposed at the lower part of tank 11 forming a spacebetween the anode 13 and cathode 12. The anode 13 is typically a solubleanode, but may also be an insoluble anode which is not consumed in theprocess.

The cathode substrate 12 and anode 13 are electrically connected bywiring 14 and 15, respectively, to a rectifier (power supply) 16. Thecathode substrate 12 for direct or pulse current has a net negativecharge so that copper ions in the solution are reduced at the cathodesubstrate forming plated copper metal on the cathode surface 12 a. Anoxidation reaction takes place at anode 13. The cathode 12 and anode 13are shown horizontally disposed but may also be vertically disposed inthe tank 11.

An electrolyte holding tank 19 contains copper electrolyte 27 which isrecycled from holding tank 19 through line 17 a, filter 26 and line 17 bto the inlet 11 a of electroplating tank 11. The electrolyte 27 as itenters the tank moves through an opening 13 a in anode 13 and moves asshown by arrows A upward to the outlets 11 b and 11 b′ of electroplatingtank 11. The anode is positioned on plate 31. Arrows B show electrolytebeing removed from holding tank 11 through outlets 11 b and 11 b′ intorecycle transfer lines 18 a and 18 b. It is preferred that outlets 11 band 11 b′ be proximate the edge of surface 12 a of cathode 12 and morepreferred that the outlet be a continuous opening around the peripheryof the electroplating tank so that the flow of electrolyte impinging onthe cathode surface is uniform across the cathode surface and theelectrolyte overflows the opening and is directed to holding tank 19 forrecycle. The electrolyte thus flows through the opening 13 a in anode 13and flows upward through tank 11 and impinges on cathode 12 as it exitsthe tank 11. A flange or plate 30 holds cathode 12 in position. As shownin the figure, electrolyte contacts only the upper side of anode 13 andonly the lower side 12 a of cathode 12. The outlet electrolyte isrecycled to holding tank 19. During operation of the plating system toplate cathode substrate 12 with a layer of copper, the electrolyte 27 ispreferably continuously recycled through holding tank 19 andelectroplating tank 11. This forms a substantially uniform electrolytecomposition in the system and contributes to the overall effectivenessof the substrate plating.

The copper electroplating bath may vary widely depending on thesubstrate to be plated and the type copper deposit desired. An acid bathis preferred and an exemplary copper plating bath because of itsdemonstrated effectiveness has a copper ion concentration of about 15 to19 g/l and a copper sulfate concentration as the pentahydrate of 59 to75 g/l. Sulfuric acid is present in an amount of about 150 to 225 g/l.Chloride ion may also be used in the bath at a level up to 90 mg/l. Thebath also preferably contains an organic additive system such asaccelerator, suppressor, and other defect reducer.

During operation of the electroplating system 10, copper metal is platedon surface 12 a of cathode substrate 12 when the rectifier 16 isenergized. A pulse current, direct current, reverse periodic current orother suitable current may be employed. The temperature of theelectrolyte may be maintained using a heater/cooler 22 wherebyelectrolyte 27 is removed from holding tank 19 and flows through line23, heater/cooler 22 and then recycled to holding tank 19 through line24.

It is an optional feature of the process that the plating system becontrolled as described in U.S. Pat. No. 6,024,856 by removing a portionof the electrolyte from the system when a predetermined operatingparameter (condition) is met and new electrolyte is added to the systemeither simultaneously or after the removal in substantially the sameamount. The new electrolyte is preferably a single liquid containing allthe materials needed to maintain the electroplating bath and system. Theaddition/removal system maintains a steady-state constant plating systemhaving enhanced plating effects such as constant plating properties.With this system and method the plating bath reaches a steady statewhere bath components are substantially a steady-state value. It ispreferred that the concentration of copper in the electrolyte bemaintained within about 3 g/l, preferably 2 g/l and most preferably 1g/l or less of the desired copper concentration for wafer platingprocesses. The copper used to make the electrolyte and the coppercontaining solution is preferably copper sulfate.

Referring now to FIG. 10, which shows another plating system 10, theplating system 10 is similar to the plating system of FIG. 9 except thata holding tank 19 is not employed. Thus, an electroplating tank 11 hastherein a horizontally disposed cathode 12 and anode 13 separated by aspace. Electrolyte 27 in the tank is circulated through the tank andremoved through outlet lines 18 a and 18 b. The outlet from the tank isrecycled to the inlet of the tank through line 17 a, filter 26 and line17 b into tank 11 at inlet 11 a. The flow of electrolyte 27 into thetank is shown by arrows A and electrolyte flow to outlets 11 b and 11 b′past cathode 12 as shown by arrows B. Anode 13 has a central opening 13a.

When a predetermined operating parameter is reached, electrolyte 27 isremoved from the apparatus through line 29 into tank or container 21 anda copper containing solution in tank 20 is fed into outlet line 18 athrough line 28. A heater or cooler 22 is shown employed in line 18 a.

The invention may be practiced using a large variety of copper baths.The electrolytic baths include acid baths and alkaline baths. A varietyof copper electroplating baths are described in the book entitled ModernElectroplating, edited by F. A. Lowenheim, John Reily & Sons, Inc.,1974, pages 183-203. Exemplary baths include copper fluoborate, copperpyrophosphate, copper cyanide, copper phosphonate and other copper metalcomplexes such as methane sulfonic acid and the preferred copperelectroplating bath comprises copper sulfate in an acid solution. Theconcentration of copper and acid may vary over wide limits. For copperor copper ions, compositions generally vary from on the order of 10 g/Lto on the order of 50 g/L, and even up to saturation, depending on theacid concentration. For example, in one embodiment the copper ionconcentration is about 17 g/L where the H₂SO₄ concentration is about 180g/L. In another embodiment, the Cu concentration is about 40 g/L wherethe H₂SO₄ concentration is about 10 g/L. The acid solution is typicallysulfuric acid in an amount up to about 300 g/l. Chloride ions may beused in the bath at levels up to about 200 mg/l.

A large variety of additives are typically used in the bath to providedesired surface finishes for the copper plated metal. Usually more thanone additive is used with each additive forming a desired function. Theadditives are generally used to initiate bottom-up filling ofinterconnect features as well as for improved metal plated appearance(brightness), structure and physical properties such as electricalconductivity. Particular additives (usually organic additives) are usedfor grain refinement, suppression of dendritic growth and improvedcovering and throwing power. Typical additives used in electroplatingare discussed in a number of references including Modern Electroplating,cited above. A particularly desirable additive system uses a mixture ofaromatic or aliphatic quaternary amines, polysulfide compounds,polyimines and polyethers. Other additives include metaloids such asselenium, tellurium and sulfur compounds.

Electrolysis conditions such as electric current concentration, appliedvoltage, electric current density, and electrolyte temperature areessentially the same as those in conventional electrolytic copperplating methods. For example, the bath temperature is typically aboutroom temperature such as about 20-27 C, but may be at elevatedtemperatures up to about 40 C or higher. The current density istypically up to about 100 amps per square foot (ASF) typically about 2to 40 ASF. It is preferred to use an anode to cathode ratio of about1:1, but this may also vary widely from about 1:4 to 4:1. The processalso uses mixing in the electroplating tank which may be supplied byagitation or preferably by the circulating flow of recycle electrolytethrough the tank. In the preferred apparatus as shown in the Figures,the flow through the electroplating tank provides a residence time ofelectrolyte in the tank of less than about 1 minute typically less than30 seconds, e.g., 10-20 seconds.

The foregoing relates only to a limited number of embodiments that havebeen provided for illustration purposes only. It is intended that thescope of invention is defined by the appended claims and thatmodifications to the embodiments above may be made that do not departfrom the scope of the invention.

The invention claimed is:
 1. A method for electroplating a copperdeposit onto a semiconductor integrated circuit device substrate withelectrical interconnect features including submicron-sized features suchthat the surface has submicron-sized reliefs therein, said substratecomprising a wafer, the method comprising: immersing the substrate intoan electroplating bath including ionic copper, a suppressor, anaccelerator, and an effective amount of a defect reducing agentcomprising a reaction product of 1-chloromethylnaphthalene andhydroxyethyl polyethylenimine; and electroplating the copper depositfrom said bath onto the substrate to fill the submicron-sized reliefswhereby the occurrence of protrusion defects from superfilling, surfaceroughness, and voiding due to uneven growth are reduced, and macro-scaleplanarity across the wafer is improved.
 2. A process as set forth inclaim 1 wherein the amount of said defect reducing agent is effective toreduce the rate at which the copper deposit subsequently undergoesrecrystallization and grain growth, whereby the deposit is characterizedby a reduced concentration of internal voids.
 3. The process as setforth in claim 1 wherein the ionic copper is present in theelectroplating bath in a concentration between 10 g/L and 50 g/L.
 4. Amethod for electroplating a copper deposit onto a semiconductorintegrated circuit device substrate having electrical interconnectfeatures including submicron-sized features such that the surface hassubmicron-sized reliefs therein, the method comprising: immersing thesubstrate into an electroplating bath including ionic copper and aneffective amount of a defect reducing agent which reduces a rate ofrecrystallization and grain growth in the copper deposit, therebyreducing the formation of internal voids within the copper depositwherein the defect reducing agent comprises a reaction product of1-chloromethylnaphthalene and hydroxyethyl polyethylenimine; andelectroplating the copper deposit from said bath onto the substrate tofill the submicron sized reliefs, which deposit subsequently undergoesrecrystallization and grain growth at a reduced rate and thereby ischaracterized by a reduced concentration of internal voids.
 5. A processas set forth in claim 4 wherein said substrate comprises a wafer theamount of said defect reducing agent is effective to reduce theoccurrence of protrusion defects from superfilling, surface roughness,and voiding due to uneven growth and to improve the macro-scaleplanarity across the wafer.
 6. The process as set forth in claim 4wherein the ionic copper is present in the electroplating bath in aconcentration between 10 g/L and 50 g/L.
 7. A method for electroplatinga copper deposit having a reduced rate of recrystallization and graingrowth onto a semiconductor integrated circuit device substrate havingelectrical interconnect features including submicron-sized features suchthat the surface has submicron-sized reliefs therein, the methodcomprising: immersing the substrate into an electroplating bathincluding ionic copper and an effective amount of a defect reducingagent which reduces a rate of recrystallization and grain growth in thecopper deposit, thereby reducing the formation of internal voids withinthe copper deposit wherein said defect reducing agent comprises aquaternized polyvinylpyridine salt; and electroplating the copperdeposit from said bath onto the substrate to fill the submicron sizedreliefs, which deposit within said submicron reliefs subsequentlyundergoes recrystallization and grain growth at a reduced rate andthereby is characterized by a reduced concentration of internal voids.8. A process as set forth in claim 7 wherein said substrate comprises awafer the amount of said defect reducing agent is effective to reducethe occurrence of protrusion defects from superfilling, surfaceroughness, and voiding due to uneven growth and to improve themacro-scale planarity across the wafer.
 9. The process as set forth inclaim 7 wherein the electroplating bath includes a suppressor and anaccelerator.
 10. The process as set forth in claim 7 wherein the ioniccopper is present in the electroplating bath in a concentration between10 g/L and 50 g/L.